Research Entomologist, Aerial Application Research Unit, USDA, ARS, College Station, TX
Research Chemist, Southern Regional Research Center, USDA, ARS, New Orleans, LA
Agricultural Engineer, Aerial Application Research Unit, USDA, ARS, College Station, TX
Pages: 12 Published: Jan 1993
Sulprofos was microencapsulated within five different polymers [medium and low molecular weight poly(methyl methacrylate), ethyl cellulose, poly(α-methylstyrene) , and cellulose acetate butyrate] by the solvent evaporation process. The microcapsules were formulated as suspensions in an aqueous solution of 88% hydrolyzed polyvinyl alcohol. Encapsulated sulprofos formulations were compared with an emulsifiable concentrate (EC) formulation of sulprofos for efficacy against eggs and larvae of tobacco budworm (TBW), Heliothis virescens (F.), on cotton. The ethyl cellulose formulation of sulprofos caused significantly greater mortality of TBW larvae (avg 74%) than the other polymeric formulations (avg 48.2%); but there was no significant difference in mortality of larvae between sulprofos EC and the ethyl cellulose formulation of sulprofos. Xanthan gum, when added to the ethyl cellulose to increase suspension of the active ingredient, significantly decreased the efficacy of the microcapsule formulation of sulprofos against TBW larvae. Overall, microencapsulation of sulprofos did not significantly affect mortality of TBW larvae on cotton. Ovicidal mortality caused by sulprofos EC averaged 4.8%. The poly(αmethylstyrene) formulation of sulprofos exhibited significantly greater ovicidal mortality of TBW than the sulprofos EC 5 days after treatment (28.7 versus 1.8%). Overall, polymeric capsules slightly increased ovicidal mortality of sulprofos (6.1 to 14.1%), but not significantly so.
microencapsulation, sulprofos, tobacco budworm, controlled release, polymeric capsules
Paper ID: STP25142S